1. Field of Invention.
This invention relates to keyboards for providing an electrical output signal on depression of a key.
2. Prior Art.
Many forms of keyboard are used or have been proposed for providing electrical outputs corresponding to the keys which have been operated. The electrical signal output may be provided for example by direct mechanical operation of contacts in an electrical circuit or by changing the inductance or capacitance in an electrical circuit or by use of magnetically operated switches, e.g. reed switches or Hall effect devices. All such keyboards require a mechanically movable key member and it is the usual practice to make the key member slidable in a suitable guide. Resilient means have to be provided to return the key member after it has been depressed.
Various methods have been proposed in the past to simplify the key construction, in particular by combining the movement supporting structure with the resilient return means, for example, by forming a whole keyboard of resilient sheet material but such techniques have raised further problems.